A variety of known display devices are projection-type displays that display a projected image. In order to observe the projected image, the observer's eye needs to be aligned with the exit pupil of the projection optical system. Therefore, in order for the projected image to be observable at a variety of positions, the exit pupil is preferably made large. In a conventional projection-type display, however, the structure of an optical system with an expanded exit pupil is large and complex. Therefore, there has been a desire for simplifying the structure of an optical system with an expanded exit pupil. It has thus been proposed to enlarge the exit pupil with an optical element that uses a volume hologram (see Non-patent Literature 1).